I've got a 3-gallon nano tank with 3 snails, a strawberry shrimp, a damselfish, and what used to be a staghorn crab. My tank is in my office, so I left it alone this weekend. When I came back in this morning, there were little red bits and a large claw in the tank and the staghorn coral shell was empty. I don't think the shrimp is the culprit, although I could be wrong. Did my damsel eat my crab or shred it or otherwise pull it out of its shell? I've had the two of them in the tank for 8 weeks with no problems whatsoever. Why would it do that all of a sudden? Does this mean I should avoid all small crabs in the future as long as my damsel is alive? Thanks for the input!